The recombinant-DNA field, many proteins have been prepared in the laboratory in an amount suitable for research purposes. However, even though techniques to produce research quantities of these proteins have been optimized, these laboratory production and purification processes are often inadequate to produce commercial quantities of the desired protein which is of a quality sufficient to be used as a human pharmaceutical.
In order to produce commercial quantities of a given protein of an appropriate quality, unique fermentation, isolation, and purification techniques are often required. Moreover, the combination of the techniques and the order in which they are practiced often affect the amount of the protein recovered and the purity of the final product.
As previously described in co-pending U.S. patent application Ser. Nos. 199,915, 238,713, 248,521 and 266,531, filed May 27, 1988, Aug. 31, 1988, Sep. 23, 1988, and Nov. 3, 1988, respectively, (now U.S. Pat. No. 5,075,222) a unique protein named human interleukin-1 inhibitor has been isolated. These applications, specifically incorporated herein by reference, also describe methods for producing recombinant human interleukin-1 inhibitor, hereinafter referred to as "IL-1i," in laboratory quantities in transformed organisms useful in laboratory methods. However, these methods did not result in production of commercial quantities of IL-1i of a quality suitable for administration to humans.
The present inventors have found certain combinations of fermentations, isolation, and purification techniques which are capable of producing commercial quantities of highly purified IL-1i. These methods are described in this application. As used herein, the term "commercial quantities" is intended to mean at least several to tens to hundreds of grams of highly purified product obtained from each 100 liters of fermentation broth. By "highly purified product" is meant a material of sufficient purity to be administered to humans. In a preferred embodiment, "highly purified product" has less than 5 E.U. per dose of endotoxin and less than 0.0025% contamination by E. coli protein.